WhatCable
USB-C cable diagnostics for macOS menu bar
Free macOS menu bar app that decodes USB-C cable capabilities, charging limits, and data speeds. Identifies bottlenecks and e-marker data.
More About WhatCable
WhatCable
WhatCable is a macOS menu bar utility that decodes USB-C cable capabilities in plain English. It identifies charging bottlenecks, data-speed limits, and e-marker data, eliminating guesswork when cables charge slowly or fail to drive displays. Open source and privacy-focused, it runs entirely on Apple Silicon.
- •Charging bottleneck detection:Shows whether the cable, charger, or Mac is limiting the charge rate, with the negotiated power profile highlighted.
- •Data-speed bottleneck analysis:Provides a plain-English verdict on what limits the link—Mac port, cable, or device—so you know if a faster cable helps.
- •Cable e-marker decoding:Decodes speed, current rating, vendor identity, and USB PD capability flags from marked USB-C cables.
- •Active transport identification:Identifies USB 2, USB 3, USB4, Thunderbolt, and DisplayPort paths under the physical port where they are connected.
- •Engineer mode:Option-click or enable raw details to reveal underlying IOKit properties for registry-level facts.
- •Device identity matching:Matches storage, hubs, docks, and peripherals back to the port they use, including negotiated USB speed.
- •Cable trust signals:Checks e-marker data against USB PD spec, flagging unusual values like zero vendor ID or reserved bit patterns.
- •Public cable database:Every reported cable is added to a searchable public database, letting you check if a cable has been seen before.
- •Notifications and dock mode:Get alerts on cable connect/disconnect, or run as a regular window instead of a menu bar icon.
- •CLI tool with watch mode:Bundled command-line tool provides readable summaries, JSON output for scripts, and live updates with --watch.
By choosing WhatCable, you turn a drawer of identical cables into a known, reliable toolkit. It eliminates the guesswork behind slow charging and failed displays, giving you clear diagnostics and confidence in every connection. Whether you're a power user or just tired of swapping cables, WhatCable makes USB-C transparent.
